Chang’e-6 Reveals New Insights into Lunar Volcanism
The Moon’s volcanic past has always intrigued scientists, but thanks to samples from the Chinese Chang’e-6 probe, we now know the far side of the Moon was volcanically active for at least 1.4 billion years. This extraordinary discovery comes from material collected during the probe’s mission, offering new perspectives on the Moon’s hidden hemisphere.
Unique Samples from the Moon’s Far Side
Chang’e-6 is the first spacecraft to return samples from the Moon’s far side. The probe brought back almost two kilograms (4.4 pounds) of lunar material, which has revealed fascinating details about this region. Among the samples was a fragment estimated to be 4.2 billion years old, making it the oldest basalt sample from the Moon with a precisely measured age.
Additionally, researchers found 107 fragments of basalt aged 2.8 billion years, evidence of a volcanic eruption at the Chang’e-6 landing site. This eruption left no trace in samples collected from the near side, highlighting the uniqueness of the far side’s geology. Previous findings from the lander had already hinted at magmatic structures in the area, making these new discoveries even more significant.
The Far Side vs the Near Side
The far side of the Moon differs greatly from the near side. While the near side boasts dark basalt plains known as maria, the far side is heavily cratered and geologically distinct. Differences in crust thickness and the concentrations of elements like thorium further accentuate this hemispheric contrast.
Understanding why these differences exist is a key scientific goal. According to Professor Yi-Gang Xu of the Guangzhou Institute of Geochemistry, the Chang’e-6 samples offer the “best opportunity to investigate the lunar global dichotomy.” Similarly, Professor Qiu-Li Li from the Chinese Academy of Sciences emphasised that studying volcanic history is essential to solving the mystery of the Moon’s hemispheric divide.
Age Confirmation Through Crater Counting
The volcanic eruption 2.8 billion years ago aligns with estimates of the Chang’e-6 landing site’s age, derived from crater counting. This technique, first established on the near side of the Moon, has proven effective on the far side, further validating the method.
These findings suggest that the Moon was likely already locked in tidal synchronisation with Earth—one face permanently facing our planet—by the time volcanism ceased on the far side.
With the insights provided by Chang’e-6, researchers are closer than ever to uncovering the Moon’s long-hidden secrets.
With inputs from Reuters